This module provides functions that are the inverse of built-in perl
functions localtime() and gmtime(). They accept a date as a six-element
array, and return the corresponding time(2) value in seconds since the
system epoch (Midnight, January 1, 1970 GMT on Unix, for example). This
value can be positive or negative, though POSIX only requires support for
positive values, so dates before the system's epoch may not work on all
operating systems.
